EP3115159B1 - Medical robotic system providing computer generated auxiliary views of a camera instrument for controlling the positioning and orienting of its tip - Google Patents

Description

FIELD OF THE INVENTION
• The present invention generally relates to medical robotic systems and in particular, to a medical robotic system providing computer generated auxiliary views of a camera instrument for controlling the positioning and orienting of its tip.
BACKGROUND OF THE INVENTION
• Medical robotic systems such as systems used in performing minimally invasive surgical procedures offer many benefits over traditional open surgery techniques, including less pain, shorter hospital stays, quicker return to normal activities, minimal scarring, reduced recovery time, and less injury to tissue. Consequently, demand for such medical robotic systems is strong and growing.
• One example of such a medical robotic system is the da Vinci® Surgical System from Intuitive Surgical, Inc., of Sunnyvale, California, which is a minimally invasive robotic surgical system. The da Vinci® Surgical System has a number of robotic arms that move attached medical devices, such as an image capturing device and Intuitive Surgical's proprietary EndoWrist® articulating surgical instruments, in response to movement of input devices by a surgeon viewing images captured by the image capturing device of a surgical site. Each of the medical devices is inserted through its own minimally invasive incision into the patient and positioned to perform a medical procedure at the surgical site. The incisions are placed about the patient's body so that the surgical instruments may be used to cooperatively perform the medical procedure and the image capturing device may view it without their robotic arms colliding during the procedure.
• To perform certain medical procedures, it may be advantageous to use a single entry aperture, such as a minimally invasive incision or a natural body orifice, to enter a patient to perform a medical procedure. For example, an entry guide may first be inserted, positioned, and held in place in the entry aperture. Instruments such as an articulatable camera and a plurality of articulatable surgical tools, which are used to perform the medical procedure, may then be inserted into a proximal end of the entry guide so as to extend out of its distal end. Thus, the entry guide provides a single entry aperture for multiple instruments while keeping the instruments bundled together as it guides them toward the work site.
• Since the entry guide generally has a relatively small diameter in order to fit through a minimally invasive incision or a natural body orifice, a number of problems may arise while teleoperating the surgical tools to perform the medical procedure and the camera to view it. For example, because the camera instrument is bundled with the surgical tools, it is limited in its positioning relative to the surgical tools and consequently, its view of the surgical tools.
• Thus, although the tips of the articulatable surgical tools may be kept in the field of view of the camera, links coupled by controllable joints which facilitate the articulatability of the surgical tools may not be in the field of view of the camera. As a consequence, the links of the surgical tools may inadvertently collide with each other (or with a link of the camera instrument) during the performance of a medical procedure and as a result, cause harm to the patient or otherwise adversely impact the performance of the medical procedure.
• Also, since the articulatable camera instrument is generally incapable of viewing its own controllable linkage, operator movement of the camera tip is especially a concern where collisions with the surgical tool links are to be avoided. Further, when intuitive control is provided to assist the operator in teleoperatively moving the surgical tools and camera, the motions of the linkages required to produce such intuitive motions of the tips of the tools and camera may not be obvious or intuitive to the operator, thus making it even more difficult for the operator to avoid collisions between links that are outside the field of view of the camera.
• WO 2008/103383 A1 discloses a medical robotic system which presents a surgeon with a video compilation that displays an endoscopic-camera derived image, a reconstructed view of the surgical field (including fiducial markers indicative of anatomical locations on or in the patient), and/or a real-time video image of the patient. The real-time image can be obtained either with the video camera that is part of the image localized endoscope or with an image localized video camera without an endoscope, or both. In certain other embodiments, the methods include the use of anatomical atlases related to pre-operative generated images derived from three-dimensional reconstructed CT, MRI, x-ray, or fluoroscopy. Images can furthermore be obtained from pre-operative imaging and spacial shifting of anatomical structures may be identified by intraoperative imaging and appropriate correction performed.
OBJECTS AND SUMMARY OF THE INVENTION
• The present invention provides a medical robotic system as set out in the appended claims. Also described is a method implemented in a medical robotic system that provides a computer generated auxiliary view of a camera for positioning and orienting the camera.
• Also described is a method implemented in a medical robotic system that provides intuitive control to an operator controlling the positioning and orienting of a camera while viewing an auxiliary view of the camera.
• Also described is a method implemented in a medical robotic system that improves an operator's understanding of the configuration of linkages of articulatable instruments that are outside of the field of view of a camera while controllably positioning and orienting the camera.
• Also described is a method for positioning and orienting a camera tip (i.e., the viewing or image capturing end of the camera), the method comprising: determining positions of mechanical elements used for positioning and orienting the camera tip; determining a position and orientation of the camera tip using the determined positions of the mechanical elements; generating a view of a computer model of the camera corresponding to a perspective of a virtual camera; displaying the view on a display screen; and controlling the positioning and orienting of the camera tip by moving the mechanical elements in response to manipulation of an input device so that the positioning and orienting of the camera tip intuitively appears to an operator who is manipulating the input device while viewing the display screen to correspond to the displayed view of the computer model of the camera.
• The present invention provides a medical robotic system having a camera, mechanical elements used for positioning and orienting a camera tip of the camera, a display screen, and an input device, the medical robotic system characterized by: a controller configured to determine positions of the mechanical elements, determine a position and orientation of the camera tip using the determined positions of the mechanical elements, generate an auxiliary view of a computer model of the camera corresponding to a perspective of a virtual camera, display the auxiliary view on the display screen, and control the positioning and orienting of the camera tip by moving the mechanical elements in response to manipulation of the input device after accounting for an offset between a current orientation of the input device with respect to the auxiliary view on the display screen and a current orientation of the camera tip with respect to a reference frame used for control of the camera tip, after mapping a current position of the input device to a current position of the camera tip so as to cancel translational offsets, and after setting a user-selectable scale factor between the input device and camera work spaces, so that the positioning and orienting of the camera tip intuitively appears to an operator who is manipulating the input device while viewing the display screen to correspond to the displayed view of the computer model of the camera.
• Additional objects, features and advantages of the various aspects of the present invention will become apparent from the following description of its preferred embodiment, which description should be taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 illustrates a top view of an operating room employing a medical robotic system utilizing aspects of the present invention.
• FIG. 2 illustrates a block diagram of components for controlling and selectively associating device manipulators to left and right hand-manipulatable input devices in a medical robotic system utilizing aspects of the present invention.
• FIGS. 3-4 respectively illustrate top and side views of an articulatable camera and a pair of articulatable surgical tools extending out of a distal end of an entry guide as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 5 illustrates a perspective view of an entry guide and its four degrees-of-freedom movement as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 6 illustrates a cross-sectional view of an entry guide with passages defined therein that extend between its proximal and distal ends as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 7 illustrates a block diagram of interacting components of an entry guide manipulator as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 8 illustrates a block diagram of interacting components of an articulatable instrument manipulator and an articulatable instrument as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 9 illustrates a flow diagram of a method for providing a computer generated auxiliary view, utilizing aspects of the present invention.
• FIG. 10 illustrates a data and processing flow diagram to determine instrument link positions and orientations using instrument joint positions and forward kinematics, as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 11 illustrates a data and processing flow diagram to determine instrument joint positions using a sensed instrument tip position and inverse kinematics, as used in a medical robotic system utilizing aspects of the present invention.
• FIGS. 12-13 respectively illustrate top and side auxiliary views as generated and displayed on a display screen by a method implemented in a medical robotic system utilizing aspects of the present invention.
• FIG. 14 illustrates top and side auxiliary views as generated and displayed in separate windows on a display screen by a method implemented in a medical robotic system utilizing aspects of the present invention.
• FIG. 15 illustrates an auxiliary view displayed adjacent to an image captured by the articulatable camera on a monitor in a medical robotic system utilizing aspects of the present invention.
• FIG. 16 illustrates an auxiliary side view of an articulatable camera having a frustum as generated and displayed by a method implemented in a medical robotic system utilizing aspects of the present invention on a display screen.
• FIG. 17 illustrates a combined display of an auxiliary view of a pair of articulatable surgical tools from a viewing point of a camera, along with an image captured by the camera, as generated and displayed by a method implemented in a medical robotic system utilizing aspects of the present invention on a display screen.
• FIG. 18 illustrates a flow diagram of a method for providing auxiliary viewing modes that correspond to device control modes in a medical robotic system, utilizing aspects of the present invention.
• FIG. 19 illustrates a flow diagram of a method for positioning and orienting a camera tip utilizing aspects of the present invention.
• FIG. 20 illustrates a side view of an articulatable camera and articulatable surgical tool extending out of a distal end of an entry guide with a zero position reference frame shown relative to a computer generated auxiliary view as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 21 illustrates a side view of an articulatable camera and articulatable surgical tool extending out of a distal end of an entry guide with an isometric auxiliary view reference frame shown relative to a computer generated auxiliary view as used in a medical robotic system utilizing aspects of the present invention.
• FIG. 22 illustrates a block diagram of a camera controller as used in a medical robotic system utilizing aspects of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• FIG. 1 illustrates, as an example, a top view of an operating room in which a medicalrobotic system100 is being utilized by aSurgeon20 for performing a medical procedure on aPatient40 who is lying face up on an operating table50. One ormore Assistants30 may be positioned near thePatient40 to assist in the procedure while theSurgeon20 performs the procedure teleoperatively by manipulatinginput devices108, 109 on asurgeon console10.
• In the present example, an entry guide (EG)200 is inserted through asingle entry aperture150 into thePatient40. Although theentry aperture150 is a minimally invasive incision in the present example, in the performance of other medical procedures, it may instead be a natural body orifice. Theentry guide200 is held and manipulated by arobotic arm assembly130.
• As with other parts of the medicalrobotic system100, the illustration of therobotic arm assembly130 is simplified inFIG. 1. In one example of the medicalrobotic system100, therobotic arm assembly130 includes a setup arm and an entry guide manipulator. The setup arm is used to position theentry guide200 at theentry aperture150 so that it properly enters theentry aperture150. The entry guide manipulator is then used to robotically insert and retract theentry guide200 into and out of theentry aperture150. It may also be used to robotically pivot theentry guide200 in pitch, roll and yaw about a pivot point located at theentry aperture150. An example of such an entry guide manipulator is theentry guide manipulator202 ofFIG. 2 and an example of the four degrees-of-freedom movement that it manipulates theentry guide200 with is shown inFIG. 5.
• Theconsole10 includes a 3-D monitor104 for displaying a 3-D image of a surgical site to the Surgeon, left and right hand-manipulatable input devices108, 109, and a processor (also referred to herein as a "controller")102. Theinput devices108, 109 may include any one or more of a variety of input devices such as joysticks, gloves, trigger-guns, hand-operated controllers, or the like. Other input devices that are provided to allow the Surgeon to interact with the medicalrobotic system100 include afoot pedal105, a conventionalvoice recognition system160 and a Graphical User Interface (GUI)170.
• Anauxiliary display screen140 is coupled to the console10 (and processor102) for providing auxiliary views to the Surgeon to supplement those shown on themonitor104. A second auxiliary display screen140' is also coupled to the console10 (and processor102) for providing auxiliary views to the Assistant(s). Aninput device180 is also coupled to the console to allow the Assistant(s) to select between available auxiliary views for display on the second auxiliary display screen140'.
• Theconsole10 is usually located in the same room as the Patient so that the Surgeon may directly monitor the procedure, is physically available if necessary, and is able to speak to the Assistant(s) directly rather than over the telephone or other communication medium. However, it will be understood that the Surgeon can also be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures. In such a case, theconsole10 may be connected to the second auxiliary display screen140' andinput device180 through a network connection such as a local area network, wide area network, or the Internet.
• As shown inFIGS. 3-4, theentry guide200 has articulatable instruments such as articulatablesurgical tools231, 241 and anarticulatable stereo camera211 extending out of its distal end. Although only twotools231, 241 are shown, theentry guide200 may guide additional tools as required for performing a medical procedure at a work site in the Patient. For example, as shown inFIG. 4, apassage351 is available for extending another articulatable surgical tool through theentry guide200 and out through its distal end. Each of thesurgical tools231, 241 is associated with one of theinput devices108, 109 in a tool following mode. The Surgeon performs a medical procedure by manipulating theinput devices108, 109 so that thecontroller102 causes corresponding movement of their respectively associatedsurgical tools231, 241 while the Surgeon views the work site in 3-D on theconsole monitor104 as images of the work site are being captured by thearticulatable camera211.
• Preferably,input devices108, 109 will be provided with at least the same degrees of freedom as their associatedtools231, 241 to provide the Surgeon with telepresence, or the perception that theinput devices108, 109 are integral with thetools231, 241 so that the Surgeon has a strong sense of directly controlling thetools231, 241. To this end, themonitor104 is also positioned near the Surgeon's hands so that it will display a projected image that is oriented so that the Surgeon feels that he or she is actually looking directly down onto the work site and images of thetools231, 241 appear to be located substantially where the Surgeon's hands are located.
• In addition, the real-time image on themonitor104 is preferably projected into a perspective image such that the Surgeon can manipulate theend effectors331, 341 of thetools231, 241 through theircorresponding input devices108, 109 as if viewing the work site in substantially true presence. By true presence, it is meant that the presentation of an image is a true perspective image simulating the viewpoint of an operator that is physically manipulating theend effectors331, 341. Thus, theprocessor102 may transform the coordinates of theend effectors331, 341 to a perceived position so that the perspective image being shown on themonitor104 is the image that the Surgeon would see if the Surgeon was located directly behind theend effectors331, 341.
• Theprocessor102 performs various functions in thesystem100. One important function that it performs is to translate and transfer the mechanical motion ofinput devices108, 109 through control signals overbus110 so that the Surgeon can effectively manipulate devices, such as thetools231, 241,camera211, andentry guide200, that are selectively associated with theinput devices108, 109 at the time. Another function is to perform various methods and controller functions described herein.
• Although described as a processor, it is to be appreciated that theprocessor102 may be implemented in practice by any combination of hardware, software and firmware. Also, its functions as described herein may be performed by one unit or divided up among different components, each of which may be implemented in turn by any combination of hardware, software and firmware. Further, although being shown as part of or being physically adjacent to theconsole10, theprocessor102 may also comprise a number of subunits distributed throughout the system.
• For additional details on the construction and operation of various aspects of a medical robotic system such as described herein, see, e.g.,U.S. Pat. No. 6,493,608 "Aspects of a Control System of a Minimally Invasive Surgical Apparatus," andU.S. Pat. No. 6,671,581 "Camera Referenced Control in a Minimally Invasive Surgical Apparatus".
• FIG. 2 illustrates, as an example, a block diagram of components for controlling and selectively associating device manipulators to theinput devices 108, 109. Various surgical tools such as graspers, cutters, and needles may be used to perform a medical procedure at a work site within the Patient. In this example, twosurgical tools 231, 241 are used to robotically perform the procedure and thecamera 211 is used to view the procedure. Thetools 231, 241 andcamera 211 are inserted through passages in theentry guide 200. As described in reference toFIG. 1, theentry guide 200 is inserted into the Patient throughentry aperture 150 using the setup portion of therobotic arm assembly 130 and maneuvered by the entry guide manipulator (EGM) 202 of therobotic arm assembly 130 towards the work site where the medical procedure is to be performed.
• Each of thedevices 231, 241, 211, 200 is manipulated by its own manipulator. In particular, thecamera 211 is manipulated by a camera manipulator (ECM) 212, the firstsurgical tool 231 is manipulated by a first tool manipulator (PSM1) 232, the secondsurgical tool 241 is manipulated by a second tool manipulator (PSM2) 242, and theentry guide 200 is manipulated by an entry guide manipulator (EGM) 202. So as to not overly encumber the figure, thedevices 231, 241, 211, 200 are not shown, only theirrespective manipulators 232, 242, 212, 202 are shown in the figure.
• Each of theinstrument manipulators 232, 242, 212 is a mechanical assembly that carries actuators and provides a mechanical, sterile interface to transmit motion to its respective articulatable instrument. Eachinstrument 231, 241, 211 is a mechanical assembly that receives the motion from its manipulator and, by means of a cable transmission, propagates the motion to its distal articulations (e.g., joints). Such joints may be prismatic (e.g., linear motion) or rotational (e.g., they pivot about a mechanical axis). Furthermore, the instrument may have internal mechanical constraints (e.g., cables, gearing, cams, belts, etc.) that force multiple joints to move together in a pre-determined fashion. Each set of mechanically constrained joints implements a specific axis of motion, and constraints may be devised to pair rotational joints (e.g., joggle joints). Note also that in this way the instrument may have more joints than the available actuators.
• In contrast, theentry guide manipulator202 has a different construction and operation. A description of the parts and operation of theentry guide manipulator202 is described below in reference toFIG. 7.
• In this example, each of theinput devices108, 109 may be selectively associated with one of thedevices211, 231, 241, 200 so that the associated device may be controlled by the input device through its controller and manipulator. For example, by placingswitches258, 259 respectively in tool following modes "T2" and "T1", the left andright input devices108, 109 may be respectively associated with the first and secondsurgical tools231, 241, which are telerobotically controlled through theirrespective controllers233, 243 (preferably implemented in the processor102) andmanipulators232, 242 so that the Surgeon may perform a medical procedure on the Patient while theentry guide200 is locked in place.
• When thecamera211 or theentry guide200 is to be repositioned by the Surgeon, either one or both of the left andright input devices108, 109 may be associated with thecamera211 orentry guide200 so that the Surgeon may move thecamera211 orentry guide200 through its respective controller (213 or203) and manipulator (212 or202). In this case, the disassociated one(s) of thesurgical tools231, 241 is locked in place relative to theentry guide200 by its controller. For example, by placingswitches258, 259 respectively in camera positioning modes "C2" and "C1", the left andright input devices108, 109 may be associated with thecamera211, which is telerobotically controlled through its controller213 (preferably implemented in the processor102) andmanipulator212 so that the Surgeon may position thecamera211 while thesurgical tools231, 241 andentry guide200 are locked in place by theirrespective controllers233, 243, 203. If only one input device is to be used for positioning the camera, then only one of theswitches258, 259 is placed in its camera positioning mode while the other one of theswitches258, 259 remains in its tool following mode so that its respective input device may continue to control its associated surgical tool.
• On the other hand, by placingswitches258, 259 respectively in entry guide positioning modes "G2" and "G1", the left andright input devices108, 109 may be associated with theentry guide200, which is telerobotically controlled through its controller203 (preferably implemented in the processor102) andmanipulator202 so that the Surgeon may position theentry guide200 while thesurgical tools231, 241 andcamera211 are locked in place relative to theentry guide200 by theirrespective controllers233, 243, 213. As with the camera positioning mode, if only one input device is to be used for positioning the entry guide, then only one of theswitches258, 259 is placed in its entry guide positioning mode while the other one of theswitches258, 259 remains in its tool following mode so that its respective input device may continue to control its associated surgical tool.
• The selective association of theinput devices108, 109 to other devices in this example may be performed by the Surgeon using theGUI170 or thevoice recognition system160 in a conventional manner. Alternatively, the association of theinput devices108, 109 may be changed by the Surgeon depressing a button on one of theinput devices108, 109 or depressing thefoot pedal105, or using any other well known mode switching technique.
• FIGS. 3-4 respectively illustrate, as examples, top and right side views of a distal end of theentry guide200 with thecamera211 andsurgical tools231, 241 extending outward. As shown in a perspective view of a simplified (not to scale)entry guide200 inFIG. 5, theentry guide200 is generally cylindrical in shape and has a longitudinal axis X' running centrally along its length. The pivot point, which is also referred to as a remote center "RC", serves as an origin for both a fixed reference frame having X, Y and Z axes as shown and an entry guide reference frame having X', Y' and Z' axes as shown. When thesystem100 is in the entry guide positioning mode, theentry guide manipulator202 is capable of pivoting theentry guide200 in response to movement of one or more associated input devices about the Z axis (which remains fixed in space) at the remote center "RC" in yaw ψ. In addition, theentry guide manipulator202 is capable of pivoting theentry guide200 in response to movement of the one or more input devices about the Y' axis (which is orthogonal to the longitudinal axis X' of the entry guide200) in pitch θ, capable of rotating theentry guide200 about its longitudinal axis X' in roll Φ, and linearly moving theentry guide200 along its longitudinal axis X' in insertion/retraction or in/out "I/O" directions in response to movement of the one or more associated input devices. Note that unlike the Z-axis which is fixed in space, the X' and Y' axes move with theentry guide200.
• As shown inFIG. 7, the entry guide manipulator (EGM)202 has four actuators701-704 for actuating the four degrees-of-freedom movement of the entry guide200 (i.e., pitch θ, yaw ψ, roll Φ, and in/out I/O) and four corresponding assemblies711-714 to implement them.
• Referring back toFIGS. 3-4, thearticulatable camera211 extends throughpassage321 and the articulatablesurgical tools231, 241 respectively extend throughpassages431, 441 of theentry guide200. Thecamera211 includes a tip311 (which houses a stereo camera connected to a camera controller and a fiber-optic cable connected to an external light source), first, second, andthird links322, 324, 326, first and second joint assemblies (also referred to herein simply as "joints")323, 325, and awrist assembly327. The firstjoint assembly323 couples the first andsecond links322, 324 and the secondjoint assembly325 couples the second andthird links324, 326 so that thesecond link324 may pivot about the firstjoint assembly323 in pitch and yaw while the first andthird links322, 326 remain parallel to each other.
• The first andsecond joints323, 325 are referred to as "joggle joints", because they cooperatively operate together so that as thesecond link324 pivots about the first joint323 in pitch and/or yaw, thethird link326 pivots about the second joint325 in a complementary fashion so that the first andthird links322, 326 always remain parallel to each other. Thefirst link322 may also rotate around its longitudinal axis in roll as well as move in and out (e.g., insertion towards the work site and retraction from the worksite) through thepassage321. Thewrist assembly327 also has pitch and yaw angular movement capability so that the camera'stip311 may be oriented up or down and to the right or left, and combinations thereof.
• The joints and links of thetools231, 241 are similar in construction and operation to those of thecamera211. In particular, thetool231 includes an end effector331 (havingjaws338, 339), first, second, andthird links332, 334, 336, first and secondjoint assemblies333, 335, and awrist assembly337 that are driven by actuators such as described in reference toFIG. 8 (plus an additional actuator for actuating the end effector331). Likewise, thetool241 includes an end effector341 (havingjaws348, 349), first, second, andthird links342, 344, 346, first and second joint assemblies343,345, and awrist assembly347 that are also driven by actuators such as described in reference toFIG. 8 (plus an additional actuator for actuating the end effector341).
• FIG. 8 illustrates, as an example, a diagram of interacting parts of an articulatable instrument (such as thearticulatable camera211 and the articulatablesurgical tools231, 241) and its corresponding instrument manipulator (such as thecamera manipulator212 and thetool manipulators232, 242). Each of the instruments includes a number of actuatable assemblies821-823, 831-833, 870 for effectuating articulation of the instrument (including its end effector), and its corresponding manipulator includes a number of actuators801-803, 811-813, 860 for actuating the actuatable assemblies.
• In addition, a number of interface mechanisms may also be provided. For example, pitch/yaw coupling mechanisms840, 850 (respectively for the joggle joint pitch/yaw and the wrist pitch/yaw) andgear ratios845, 855 (respectively for the instrument roll and the end effector actuation) are provided in a sterile manipulator/instrument interface to achieve the required range of motion of the instrument joints in instrument joint space while both satisfying compactness constraints in the manipulator actuator space and preserving accurate transmissions of motion across the interface. Although shown as asingle block840, the coupling between the jogglejoint actuators801, 802 (differentiated as #1 and #2) and joggle joint pitch/yaw assemblies821, 822 may include a pair of coupling mechanisms - one on each side of the sterile interface (i.e., one on the manipulator side of the interface and one on the instrument side of the interface). Likewise, although shown as asingle block850, the coupling between thewrist actuators812, 813 (differentiated as #1 and #2) and wrist pitch/yawjoint assemblies832, 833 may also comprise a pair of coupling mechanisms - one on each side of the sterile interface.
• Both the jogglejoint pitch assembly821 and the jogglejoint yaw assembly822 share the first, second and third links (e.g.,links322, 324, 326 of the articulatable camera211) and the first and second joints (e.g., joints322, 325 of the articulatable camera211). In addition to these shared components, the joggle joint pitch andyaw assemblies821, 822 also include mechanical couplings that couple the first and second joints (through joggle coupling840) to the joggle joint pitch andyaw actuators801, 802 so that the second link may controllably pivot about a line passing through the first joint and along an axis that is latitudinal to the longitudinal axis of the first link (e.g., link322 of the articulatable camera211) and the second link may controllably pivot about a line passing through the first joint and along an axis that is orthogonal to both the latitudinal and longitudinal axes of the first link.
• The in/out (I/O)assembly823 includes the first link (e.g., link322 of the articulatable camera211) and interfaces through a drive train coupling the in/out (I/O) actuator803 to the first link so that the first link is controllably moved linearly along its longitudinal axis by actuation of the I/O actuator803. Theroll assembly831 includes the first link and interfaces through one or more gears (i.e., having the gear ratio845) that couple a rotating element of the roll actuator811 (such as a rotor of a motor) to the first link so that the first link is controllably rotated about its longitudinal axis by actuation of theroll actuator811.
• The instrument manipulator (e.g., camera manipulator212) includeswrist actuators812, 813 that actuate throughwrist coupling850 pitch andyaw joints832, 833 of the wrist assembly (e.g.,wrist327 of the articulatable camera211) so as to cause the instrument tip (e.g., camera tip311) to controllably pivot in an up-down (i.e., pitch) and side-to-side (i.e., yaw) directions relative to the wrist assembly. Thegrip assembly870 includes the end effector (e.g.,end effector331 of the surgical tool231) and interfaces through one or more gears (i.e., having the gear ratio855) that couple thegrip actuator860 to the end effector so as to controllably actuate the end effector.
• FIG. 9 illustrates, as an example, a flow diagram of a method implemented incontroller102 of the medicalrobotic system100 for providing a computer generated auxiliary view including articulatable instruments, such as thearticulatable camera211 and/or one or more of the articulatablesurgical tools231, 241, extending out of the distal end of theentry guide200. For the purposes of this example, it is assumed that thearticulatable camera211 andsurgical tools231, 241 extend out of the distal end of theentry guide200 and are included in the auxiliary view. However, it is to be appreciated that the method is applicable to any combination of articulatable instruments, including those without an articulatable camera and/or those with an alternative type of image capturing device such as an ultrasound probe.
• In901, the method determines whether or not an auxiliary view is to be generated. If the determination in901 is NO, then the method loops back to periodically check to see whether the situation has changed. On the other hand, if the determination in901 is YES, then the method proceeds to902. The indication that an auxiliary view is to be generated may be programmed into thecontroller102, created automatically or created by operator command.
• In902, the method receives state information, such as positions and orientations, for each of theinstruments211, 231, 241 and theentry guide200. This information may be provided by encoders coupled to the actuators in theirrespective manipulators212, 232, 242, 202. Alternatively, the information may be provided by sensors coupled to joints and/or links of theinstruments211, 231, 241 and theentry guide manipulator202, or the coupling mechanisms, gears and drive trains of the interface between corresponding manipulators and instruments, so as to measure their movement. In this second case, the sensors may be included in theinstruments211, 231, 241 andentry guide manipulator202 such as rotation sensors that sense rotational movement of rotary joints and linear sensors that sense linear movement of prismatic joints in theinstruments211, 231, 241 andentry guide manipulator202. Other sensors may also be used for providing information of the positions and orientations of theinstruments211, 231, 241 andentry guide200 such as external sensors that sense and track trackable elements, which may be active elements (e.g., radio frequency, electromagnetic, etc.) or passive elements (e.g., magnetic, etc.), placed at strategic points on theinstruments211, 231, 241, theentry guide200 and/or the entry guide manipulator202 (such as on their joints, links and/or tips).
• In903, the method generates a three-dimensional computer model of thearticulatable camera211 and articulatablesurgical tools231, 241 extending out of the distal end of theentry guide200 using the information received in902 and the forward kinematics and known constructions of theinstruments211, 231, 241,entry guide200, andentry guide manipulator202. The generated computer model in this example may be referenced to the remote center reference frame (X, Y, Z axes) depicted inFIG. 5. Alternatively, the generated computer model may be referenced to a reference frame defined at the distal end of theentry guide200. In this latter case, if the orientation and extension of theentry guide200 from the remote center does not have to be accounted for in the auxiliary view that is being generated by the method, then the position and orientation information for theentry guide200 may be omitted in902.
• For example, referring toFIG. 10, if the state information received in902 is the instruments'joint positions1001, then this information may be applied to the instruments'forward kinematics1002 using the instruments'kinematic models1003 to generate the instruments' link positions andorientations1005 relative toreference frame1004. The same process may also be generally applied if the state information received in902 is sensed states of the joggle coupling and gear mechanisms in the manipulator/instrument interfaces.
• On the other hand, referring toFIG. 11, if the state information received in902 is the instruments' tip positions1101 (in the reference frame1004), then this information may be applied to the instruments'inverse kinematics1102 using the instruments'kinematic models1003 and the sensor reference frame to generate the instruments'joint positions1001. The instruments'joint positions1001 may then be applied as described in reference toFIG. 10 to generate the instruments' link positions andorientations1005 relative toreference frame1004.
• Alternatively, also referring toFIG. 11, if the state information provided in902 is limited to only the camera's tip position, then the positions of the tips of thesurgical tools231, 241 may be determined relative to the camera reference frame by identifying the tips in the image captured by thecamera211 using conventional image processing techniques and then translating their positions to thereference frame1004, so that the positions of the camera and tool tips may be applied as described in reference toFIGS. 10, 11 to generate the instruments' link positions andorientations1005 relative to thereference frame1004.
• In904, the method adjusts the view of the computer model of thearticulatable camera211 and articulatablesurgical tools231, 241 extending out of the distal end of theentry guide200 in the three-dimensional space of the reference frame to a specified viewing point (wherein the term "viewing point" is to be understood herein to include position and orientation). For example,FIG. 12 illustrates a top view of thearticulatable camera211 and articulatablesurgical tools231, 241 extending out of the distal end of theentry guide200 which corresponds to a viewing point above and slightly behind the distal end of theentry guide200. As another example,FIG. 13 illustrates a side view of thearticulatable camera211 and articulatablesurgical tools231, 241 extending out of the distal end of theentry guide200 which corresponds to a viewing point to the right and slightly in front of the distal end of theentry guide200. Note that although the auxiliary views depicted inFIGS. 12-13 are two-dimensional, they may also be three-dimensional views since three-dimensional information is available from the generated computer model. In this latter case, theauxiliary display screen140 that they are being displayed on would have to be a three-dimensional display screen like themonitor104.
• The viewing point may be set at a fixed point such as one providing an isometric (three-dimensional) view from the perspective shown inFIG. 12. This perspective provides a clear view to the surgeon of thearticulatable camera211 and the articulatablesurgical tools231, 241 when thetools231, 241 are bent "elbows out" as shown (which is a typical configuration for performing a medical procedure using thesurgical tools231, 241). On the other hand, when a third surgical tool is being used (e.g., inserted in thepassage351 shown inFIG. 6), a side view from the perspective ofFIG. 13 may additionally be useful since the third surgical tool may be beneath thearticulatable camera211 and therefore obscured by it in the perspective shown inFIG. 12.
• Rather than setting the viewing point to a fixed point at all times, the viewing point may also be automatically changed depending upon the control mode (i.e., one of the modes described in reference toFIG. 2) that is operative at the time. As an example,FIG. 18 illustrates a method for automatically changing the auxiliary viewing mode depending upon the control. mode currently operative in the medicalrobotic system100. In particular, using this method, a first auxiliary viewing mode is performed in1802 when the medicalrobotic system100 is determined in1801 to be in a tool following mode, a second auxiliary viewing mode is performed in1804 when the medicalrobotic system100 is determined in1803 to be in an entry guide positioning mode, and a third auxiliary viewing mode is performed in1806 when the medicalrobotic system100 is determined in1805 to be in a camera positioning mode. The viewing modes for each control mode are selected so as to be most beneficial to the surgeon for performing actions during that mode. For example, in the tool following and camera positioning modes, either or both thesurgical tools231, 241 andcamera211 is being moved at the time and therefore, an auxiliary view of thearticulatable camera211 and articulatablesurgical tools231, 241 extending out of the distal end of theentry guide200, such as depicted inFIGS. 12 and13, is useful to avoid collisions between links that are out of the field of view of thecamera211. On the other hand, in the entry guide positioning mode, thearticulatable camera211 and the articulatablesurgical tools231, 241 are locked in position relative to theentry guide200 and therefore, an auxiliary view providing information on other things such as depicted inFIGS. 16 and17 may be useful.
• Alternatively, operator selectable means for changing the viewing point during the performance of a medical procedure may be provided. For example, theGUI170 orvoice recognition system160 may be adapted to provide an interactive means for the Surgeon to select the viewing mode and/or change the viewing point of an auxiliary view of thearticulatable camera211 and/or articulatablesurgical tools231, 241 as they extend out of the distal end of theentry guide200. Buttons on theinput devices108, 109 or thefoot pedal105 may also be used for Surgeon selection of viewing modes. For the Assistant(s), theinput device180 may be used along with a GUI associated with the display screen140' for selection of viewing modes. Thus, the viewing modes that the Surgeon and Assistant(s) see at the time may be optimized for their particular tasks at the time. Examples of such operator selectable viewing modes and viewing angles are depicted inFIGS. 12-17.
• In905, the method renders the computer model. Rendering in this case includes adding three-dimensional qualities such as known construction features of theinstruments211, 231, 241 and the distal end of theentry guide200 to the model, filling-in any gaps to make solid models, and providing natural coloring and shading. In addition, rendering may include altering the color or intensity of one or more of theinstruments211, 231, 241 (or one or more of their joints or links or portions thereof) so that the instrument (or joint or link or portion thereof) stands out for identification purposes.
• Alternatively, the altering of the color, intensity, or frequency of blinking on and off (e.g., flashing) of one or more of theinstruments211, 231, 241 (or their joints, links, or portions thereof) may serve as a warning that the instrument (or joint or link or portion thereof) is approaching an undesirable event or condition such as nearing a limit of its range of motion or getting too close to or colliding with another one of the instruments. When color is used as a warning, the color may go from a first color (e.g., green) to a second color (e.g., yellow) when a warning threshold of an event to be avoided (e.g., range of motion limitation or collision) is reached, and from the second color to a third color (e.g., red) when the event to be avoided is reached. When intensity is used as a warning, the intensity of the color changes as the instrument (or portion thereof) moves past the warning threshold towards the event to be avoided with a maximum intensity provided when the event is reached. When blinking of the color is used as a warning, the frequency of blinking changes as the instrument (or portion thereof) moves past the warning threshold towards the event to be avoided with a maximum frequency provided when the event is reached. The warning threshold may be based upon a range of motion of the instrument (or portion thereof, such as its joints) or upon a distance between the instrument (or portion thereof) and another instrument (or portion thereof) that it may collide with. Velocity of the instrument's movement may also be a factor in determining the warning threshold. The warning threshold may be programmed by the operator, using theGUI170, for example, or determined automatically by a programmed algorithm in theprocessor102 that takes into account other factors such as the velocity of the instruments' movements.
• Alternatively, the altering of the color, intensity, or frequency of blinking on and off (e.g., flashing) of one or more of theinstruments211,231,241 (or their joints, links, or portions thereof) may serve as an alert that the instrument (or joint or link or portion thereof) is approaching a desirable event or condition such as an optimal position or configuration for performing or viewing a medical procedure. In this case, an alert threshold may be defined so that the color, intensity, and/or blinking of the one or more of theinstruments211,231,241 (or their joints, links, or portions thereof) may change in a similar manner as described previously with respect to warning thresholds and undesirable events or conditions, except that in this case, the change starts when the alert threshold is reached and maximizes or otherwise ends when the desirable event or condition is reached or otherwise achieved. The alert threshold may also be programmed by the operator or determined automatically by a programmed algorithm in a conceptually similar manner as the warning threshold.
• As an example of such highlighting of an instrument for identification, warning or alerting purposes,FIG. 15 shows an auxiliary view of thecamera211 andsurgical tools231,241 in awindow1502, where thecamera211 has been highlighted. As an example of such highlighting of joints of instruments for identification, warning or alerting purposes,FIG. 12 shows joints of thesurgical tools231, 241 that have been highlighted. As an example of highlighting portions of instruments for warning purposes,FIG. 14 shows aportion1402 of thesurgical tool241 and aportion1403 of thecamera211 highlighted to indicate that these portions are dangerously close to colliding.
• Rendering may also include overlaying the image captured by thecamera211 over the auxiliary view when the viewing point of the auxiliary image is the same as or directly behind that of thecamera211. As an example,FIG. 17 illustrates a capturedimage1700 of thecamera211 rendered as an overlay to an auxiliary view ofsurgical tools231, 241 which has been generated from a viewing point of (or right behind) thecamera211. In this example, the auxiliary view of thesurgical tools231, 241 being displayed on the auxiliary display screen140 (and/or the auxiliary display screen140') includes portions (e.g.,1731,1741) in the overlaying capturedimage1700 and portions (e.g.,1732,1742) outside of the overlaying capturedimage1700. Thus, the portions of thesurgical tools231,241 outside of the capturedimage1700 provide the Surgeon with additional information about their respective links or articulating arms that are out of the field of view of thecamera211. Highlighting of the instrument portions (e.g.,1732,1742) outside of the capturedimage1700 may also be done for identification purposes or to indicate a warning or alerting condition as described above. Overlaying the capturedimage1700 onto the auxiliary view also has the advantage in this case of showing ananatomic structure360 which is in front of thesurgical tools231,241 that would not otherwise normally be in the auxiliary view. Although this example shows the capturedimage1700 overlaying the auxiliary view on theauxiliary display screen140, in another rendering scheme, the auxiliary view may overlay the captured image that is being displayed on themonitor104.
• Rather than overlaying the captured image, rendering may also include using the auxiliary view to augment the image captured by thecamera211 by displaying only the portions of theinstruments231, 241 that are not seen in the captured image (i.e., the dotted line portion of theinstruments231,241 inFIG. 17) in proper alignment and adjacent the captured image in a mosaic fashion.
• In addition to, or in lieu of, overlaying the captured image over the auxiliary view or augmenting the captured image with the auxiliary view, rendering may also include providing other useful information in the auxiliary view. As an example,FIG. 16 illustrates an auxiliary side view of anarticulatable camera211 with afrustum1601 rendered on the auxiliary view so as to be displayed on theauxiliary display140 as emanating from, and moving with, thecamera tip311. Note that although thefrustum1601 is shown in the figure as a truncated cone, it may also appear as a truncated pyramid to correspond to the captured image that is shown on themonitor104. The sides of thefrustum1601 indicate a viewing range of thecamera211 and thebase1602 of thefrustum1601 displays animage1650 that was captured by thecamera211. Note that for simplification purposes, thesurgical tools231, 241 normally in the auxiliary view have been removed for this example. As another example,FIG. 14 shows a semi-translucent sphere or bubble1401 (preferably colored red) which is displayed by the method as part of the rendering process when a warning threshold is reached so as to indicate to the operator that the highlightedportions1402,1403 of thesurgical tool241 andcamera211 are dangerously close to colliding. In this case, the highlightedportions1402,1403 are preferably centered within the sphere. As yet another example,FIG. 14 also shows a marker orother indicator1410 indicating an optimal position for thecamera tip311 for viewing the end effectors of thesurgical tools231,241 as they are being used to perform a medical procedure. The optimal position may be determined, for example, by finding a location where the tips of the end effectors are equidistant from a center of the captured image.
• In906, the method causes the rendered computer model (i.e., the auxiliary view) to be displayed on one or more displayed screens (e.g.,140 and140') from the perspective of the selected viewing point. As shown inFIGS. 12-14 and16-17, the auxiliary view is displayed on theauxiliary display screen140. As shown inFIG. 14, more than one auxiliary view may be displayed at one time (e.g., top and side perspectives may be provided at the same time respectively inwindows1421 and1422). As shown inFIG. 15, the auxiliary view may also be displayed on theprimary monitor104 in awindow1502 that is adjacent to an image captured by thearticulatable camera211 which is being shown in anotherwindow1501. Although thewindows1501 and1502 appear in this example to be the same size, it is to be appreciated that the position and size of theauxiliary view window1502 may vary and still be within the scope of the present invention. Also, as previously mentioned, the auxiliary view may be overlayed the captured image in thewindow1501 instead of in its ownseparate window1502. In such case, the overlayed auxiliary view may be switched on and off by the Surgeon so as not to clutter the captured image during the performance of a medical procedure. The switching on and off in this case may be performed by depressing a button on one of theinput devices108,109 or depressing thefoot pedal105. Alternatively, it may be done by voice activation using thevoice recognition system160 or through Surgeon interaction with theGUI170 or using any other conventional function switching means.
• After completing906, the method then loops back to901 to repeat901-906 for the next processing cycle of thecontroller102.
• When the Surgeon desires to reposition thecamera tip311 to a more advantageous position and/or orientation to view a medical procedure being or to be performed at a work site in the Patient, one or both of theinput devices108,109 may be used to do so by temporarily associating it/them with thecamera manipulator212. One way that the Surgeon may perform such repositioning is for him or her to view images on the 3-D monitor104 that were captured by the stereoscopic camera in thecamera tip311, such as the image shown inwindow1501 ofFIG. 15, and use the captured images to guide his or her manipulation of the input device. This type of camera control is referred to as "image referenced control" since the Surgeon uses the image captured by thecamera211 as a reference for his or her controlling of the camera movement (i.e., the motion of theinput device108 corresponds to the motion of thecamera tip311 with respect to the captured image). Although image referenced control may be useful when the Surgeon is fine tuning the position and/or orientation of thecamera tip311, for larger movements problems may occur as a result of unintentional collisions between instrument links outside the field of view of thecamera211. In this latter case, an "instrument referenced control" may be more desirable where an auxiliary image of thecamera211 andtools231, 241 extending out of the distal end of theentry guide200, such as shown inwindow1502 ofFIG. 15, may be preferable for guiding the Surgeon's manipulation of the input device (i.e., the motion of theinput device108 corresponds to the motion of thecamera tip311 with respect to the auxiliary image).
• FIG. 19 illustrates, as an example of "instrument referenced control", a flow diagram of a method implemented in the medicalrobotic system100 for positioning and orienting thetip311 of thearticulatable camera instrument211 in response to operator manipulation of the input device108 (in camera positioning mode) while the operator views a computer generated auxiliary view of thecamera211 on either thedisplay screen140 or theconsole monitor104. Although bothinput devices108,109 may be used for positioning and orienting thecamera211, such as a bicycle "handlebar" type control, the present example assumes that only one input device108 (also referred to herein as the "master" or "master manipulator") is used so that theother input device109 may still be associated with and control itstool231.
• In1901, a determination is made whether the medical robotic system is in camera positioning mode. As previously described in reference toFIG. 2, this may be determined for theleft input device108 by checking the state of itsswitch258. If theswitch258 is in the "C2" position, then theinput device108 is in camera positioning mode. Otherwise, theinput device108 is not in camera positioning mode.
• If the determination in1901 is NO, then the method periodically loops back (e.g., at each processing cycle or a programmable multiple of a processing cycle) to check the current status of theswitch258. On the other hand, if the determination in1901 is YES, then the method performs preparatory tasks1902-1906 before enabling control over the positioning and orienting of thecamera tip311 by theinput device108 in1907.
• In1902, the othermedical devices241,200 associated with theinput device108 are soft-locked so that they are commanded to remain in their present stationary state by theircontrollers242,202.
• In1903, the method computes the reference frame which is used for control purposes (the "control reference frame"). This reference frame is necessary to map between the Cartesian motion of themaster108 and the Cartesian motion of thecamera tip311. The reference frame is preferably fixed in space during camera positioning mode for ease of computation. Thus, a reference frame defined by thecamera tip311, such as in tool following mode, is not desirable in camera positioning mode because in camera positioning mode, thecamera tip311 is moving and therefore, even though its state is determinable, its pose is not clearly perceivable by the Surgeon. Therefore, the Surgeon may find it more difficult in this situation to position thecamera tip311 at the desired location with respect to the Patient's anatomy using themaster108.
• As one possible reference frame that may be used,FIG. 20 illustrates a so-called "zero position"reference frame2002 which corresponds to the position and orientation where thejoints323,325,327 are rotated so that thelinks321,324,326 are in a straight line and their insertion position is a fully retracted position (i.e., thecamera tip311 is just inside thepassage321 of the entry guide200). In this position, a reference frame defined at the camera tip (i.e., the camera reference frame2010) coincides with the "zero position"reference frame2002. This frame has the property of being aligned with theentry guide200 and is centered with respect to the workspace of thecamera tip311. Therefore, the range of motion limits (perceived by the operator through haptic feedback on the input device108) can be used to find the center position of thecamera tip311 and the operator can easily understand how thecamera instrument211 moves in response to the motions of his or her arm/hand. In other words, the kinesthetic mapping between user arm/hand andcamera tip311 is aligned to the visual mapping between the camera motion and the auxiliary view seen by the Surgeon at theconsole104 and/orauxiliary display140.
• As another possible reference frame that may be used,FIG. 21 illustrates an "isometric auxiliary view"reference frame2102 which corresponds to a viewing point of the auxiliary view being displayed on the auxiliary display140 (such as shown inFIG. 12) and/or monitor104 (such as shown inwindow1502 ofFIG. 15).The viewing point in this case may be thought of as a view taken from the perspective of avirtual camera2103 whose position and orientation is preferably fixed in space during the camera positioning mode. Thereference frame2102 is defined at the tip (i.e., viewing end) of thevirtual camera2103 and its position and orientation are computed so that it has an azimuth angle α with respect to a focal point2104 (of the virtual camera2103) on the centrallongitudinal axis2101 of thepassage321 of theentry guide200 through which thecamera instrument211 extends. In particular, the location of thefocal point2104 along thelongitudinal axis2101 and the size of the azimuth angle α are selected so that thevirtual camera 2103 has a slight elevation that provides adequate depth perception in the isometric rendering of the auxiliary view and its field ofview2106 includes the links of thecamera instrument 211 andsurgical tool231 during the camera positioning mode. User studies have indicated that an angle α of approximately 25 degrees is particularly desirable for this purpose. The symmetry properties of the "zero position" reference frame are also applicable in the "auxiliary view" reference frame, with the potential advantage that the operator can use the isometric view to drive the position and orientation of thecamera tip311 and have entirely consistent haptic feedback in that frame.
• In1904, the orientation of a hand-grippable part of the input device108 (referred to herein as the masterorientation") is aligned so that the master orientation with respect to the auxiliary view being displayed on the 3-D monitor104 is the same as the current orientation of thecamera tip311 with respect to the reference frame computed in 1903 for camera control. Alternatively, this orientation alignment may be avoided by, for example, computing and accounting for the offset between the current master orientation and the current camera orientation so that the master angular motions with respect to the initial orientation are used to command the movement of thecamera tip311.
• In1905, the current position of the hand-grippable part of theinput device108 is mapped to the current position of thecamera tip311 so as to cancel translational offsets, and in1906, user-selectable scaling factors are set between theinput device 108 and thecamera 211 workspaces.
• In1907, the camera controller (CTRLC)213 is enabled so that theinput device108 now controls the positioning and orienting of thearticulatable camera instrument 211 through the
  camera controller (CTRLC)213 and manipulator (ECM)212, and in1908, thecamera tip311 is moved to the desired position and/or orientation. A description of thecamera controller213 using the control reference frame is provided below in reference toFIG. 22.
• Once thecamera tip311 has been positioned and/or oriented as desired, then the method performs preparatory tasks1909-1910 before enabling control over thetool241 by theinput device108 in1911. In particular, in1909, thecamera211 is soft-locked so that it is commanded to remain in its present stationary state (i.e., the desired position and/or orientation) by thecamera controller213, and in1910, the master orientation is aligned with that of thetool241.
• FIG. 22 illustrates, as an example, a block diagram of the camera controller (CTRLC)213 for controlling movement of the camera manipulator (ECM)212 (also referred to herein as "slave manipulator" or "slave") and consequently, the position and orientation of thetip311 of thecamera instrument211, as commanded by movement of the input device108 (also referred to herein as "master manipulator" or "master") by the Surgeon.
• Theinput device108 includes a number of links connected by joints so as to facilitate multiple degrees-of-freedom movement. For example, as the Surgeon moves theinput device108 from one position to another, sensors associated with the joints of theinput device108 sense such movement at sampling intervals (appropriate for the processing speed of thecontroller102 and camera control purposes) and provide digital information indicating such sampled movement in joint space to inputprocessing block2210.
• Input processing block2210 processes the information received from the joint sensors of theinput device108 to transform the information into a corresponding desired position and velocity for thecamera tip311 in its Cartesian space relative to a reference frame associated with the position of the Surgeon's eyes (the "eye reference frame") by computing a joint velocity from the joint position information and performing the transformation using a Jacobian matrix and eye related information using well-known transformation techniques.
• Scale and offset processing blocks2201 receives the processedinformation2211 from theinput processing block2210 and applies scale and offset adjustments to the information so that the resulting movement of thecamera tip311 and consequently, its computer generated auxiliary view being viewed by the Surgeon at the time on themonitor104 and/orauxiliary display140 appears natural and as expected by the Surgeon. The scale adjustment is useful where small movements of thecamera tip311 are desired relative to larger movement of theinput device108 in order to allow more precise movement of thecamera tip311 as it views the work site. An offset adjustment is applied for aligning theinput device108 with respect to the Surgeon's eyes as he or she manipulates theinput device108 to command movement of thecamera tip311 through the auxiliary view that is being displayed at the time on themonitor104 and/orauxiliary display140.
• Asimulated camera block2204 receives theoutput2221 of the scale and offsetprocessing block2201 and transforms the commanded position and velocity for thecamera tip311 from the Cartesian space of the eye reference frame to the joint space of thecamera manipulator212 using its inverse kinematics while avoiding singularities in its operation and limiting the commanded joint positions and velocities to avoid physical limitations or other constraints such as avoiding harmful contact with tissue or other parts of the Patient. To perform such transformation, a mapping is performed between the eye frame and the control reference frame (provided by the reference frame computation block2250) and another mapping is performed between a tip of the hand-grippable part of themaster108 and thecamera tip311. Note that these mappings preserve orientations while offsets are compensated for in the scale and offsetblock2201. Once the mappings are established, the inverse and forward kinematics blocks2204,2206 use this information to perform their computations since the mappings describe the positions and orientations of the master and camera tips with respect to the control reference frame.
• Theoutput2224 of thesimulated camera block2204 is then provided to ajoint controller block2205 and aforward kinematics block2206. Thejoint controller block2205 includes a joint control system for each controlled joint (or operatively coupled joints such as "joggle joints") of the camera instrument 211 (such as translational and orientational assemblies shown and described in reference toFIG. 8). Theoutput2224 of thesimulated camera block2204 provides the commanded value for each joint of thecamera instrument211. For feedback control purposes, sensors associated with each of the controlled joints of thecamera instrument211 providesensor data2232 back to thejoint controller block2205 indicating the current position and/or velocity of each joint of thecamera instrument211. The sensors may sense this joint information either directly (e.g., from the joint on the camera instrument211) or indirectly (e.g., from the actuator in thecamera manipulator212 driving the joint). Each joint control system in thejoint controller 2205 then generates torque commands for its respective actuator in thecamera manipulator212 so as to drive the difference between the commanded and sensed joint values to zero in a conventional feedback control system manner.
• Theforward kinematics block2206 transforms theoutput2224 of thesimulated camera block2204 from joint space back to Cartesian space relative to the eye reference frame using the forward kinematics of thecamera instrument211 with respect to the control reference frame (provided by the reference frame computation block2250). The scale and offsetblock2201 performs an inverse scale and offset function on theoutput2242 of theforward kinematics block2206 before passing itsoutput2212 to theinput processing block2210 where an error value is calculated between itsoutput2211 andinput2212. If no limitation or other constraint had been imposed on theinput2221 to thesimulated camera block2204, then the calculated error value would be zero. On the other hand, if a limitation or constraint had been imposed, then the error value is not zero and it is converted to a torque command that drives actuators in theinput device108 to provide force feedback felt by the hands of the Surgeon. Thus, the Surgeon becomes aware that a limitation or constraint is being imposed by the force that he or she feels resisting his or her movement of theinput device108 in that direction. In addition to this force feedback, forces coming from other sensors or algorithms (e.g., a force/pressure sensor or an algorithm to avoid the work volume of the surgical tools to prevent collisions) may be superimposed on the force feedback.
• Anoutput2241 of theforward kinematics block2206 may also be provided to thesimulated camera block2204 for control purposes. For example, the simulated position output may be fed back and compared with the commanded position.
• Although the various aspects of the present invention have been described with respect to a preferred embodiment, it will be understood that the invention is entitled to full protection within the full scope of the appended claims.

Claims (13)

1. A medical robotic system (100) having a camera (211), mechanical elements (322-327) used for positioning and orienting a camera tip (311) of the camera (211), a display screen (140, 104), and an input device (108, 109), the medical robotic system (100)characterized by:
   a controller (102) configured to
   determine positions of the mechanical elements (322-327),
   determine a position and orientation of the camera tip (311) using the determined positions of the mechanical elements (322-327),
   generate an auxiliary view of a computer model of the camera (211) corresponding to a perspective of a virtual camera (2103),
   display the auxiliary view on the display screen (140, 104), and
   control the positioning and orienting of the camera tip (311) by moving the mechanical elements (322-327) in response to manipulation of the input device (108, 109) after accounting for an offset between a current orientation of the input device (108, 109) with respect to the auxiliary view on the display screen (140, 104) and a current orientation of the camera tip (311) with respect to a reference frame used for control of the camera tip (311), after mapping a current position of the input device (108, 109) to a current position of the camera tip (311) so as to cancel translational offsets, and after setting a user-selectable scale factor between the input device (108, 109) and camera (211) work spaces, so that the positioning and orienting of the camera tip (311) intuitively appears to an operator who is manipulating the input device (108, 109) while viewing the display screen (140, 104) to correspond to the displayed view of the computer model of the camera (211).
2. The medical robotic system (100) according to claim 1, wherein the controller (102) is configured to determine the positions of the mechanical elements (322-327) using information provided by sensors that sense the positions.
3. The medical robotic system (100) according to claim 1, wherein the mechanical elements (322-327) include joints (323, 325, 327) used to position and orient the camera tip (311).
4. The medical robotic system (100) according to claim 1, wherein the mechanical elements (322-327) include links (322, 324, 326) used to position and orient the camera tip (311).
5. The medical robotic system (100) according to claim 1, further comprising: actuators (801-803, 811-813) used to position the mechanical elements (322-327), wherein the controller (102) is configured to determine the positions of the mechanical elements (322-327) using information provided by encoders that sense actuation of the actuators (801-803, 811-813).
6. The medical robotic system (100) according to claim 1, wherein the camera (211) is an articulatable camera instrument including the mechanical elements (322-327) and the controller (102) is configured to determine the positions of the mechanical elements (322-327) by receiving state information of the camera tip (311) and generating the positions of the mechanical elements (322-327) by applying the received state information to inverse kinematics of the articulatable camera instrument.
7. The medical robotic system (100) according to claim 1, wherein the camera (211) is an articulatable camera instrument including the mechanical elements (322-327), wherein the mechanical elements include links and joints, and the controller (102) is configured to generate positions and orientations of the links with respect to the perspective of the virtual camera by applying the determined positions of the joints of the mechanical elements (322-327) to forward kinematics of the articulatable camera instrument and by using a kinematic model of the articulatable camera instrument.
8. The medical robotic system (100) according to claim 1, wherein the controller (102) is configured to generate the view of the computer model of the camera (211) corresponding to the perspective of the virtual camera (2103) by generating a three-dimensional computer model of the camera (211) and translating the three-dimensional computer model to the perspective of the virtual camera (2103).
9. The medical robotic system (100) according to claim 8, further comprising: an entry guide (200), wherein the camera (211) is an articulatable camera instrument extending out the entry guide (200), the virtual camera (2103) has identical characteristics as the camera (211), and the perspective of the virtual camera (2103) is at a position and orientation from which the camera instrument extending out of the entry guide (200) is within a field of view of the virtual camera (2103).
10. The medical robotic system (100) according to claim 9, further comprising: at least one articulatable instrument (231, 241), wherein the at least one articulatable instrument (231, 241) extends out of the entry guide (200) along with the articulatable camera instrument (211) and the perspective of the virtual camera (2103) is at a position and orientation from which the at least one articulatable instrument (231, 241) and the articulatable camera instrument (211) extending out of the entry guide (200) are at least partially within the field of view of the virtual camera (2103).
11. The medical robotic system (100) according to claim 1, further comprising an entry guide (200), wherein the camera (211) is an articulatable camera instrument extending out the entry guide (200) and the reference frame associated with the virtual camera (2103) is defined as a Cartesian reference frame having an origin at the position of the virtual camera (2103) and oriented such that one axis of the reference frame points to a focal point on a longitudinal axis extending between proximal and distal ends of the entry guide (200).
12. The medical robotic system (100) according to claim 1, wherein the controller (102) is configured to:

    disengage control of an instrument (231, 241) associated with the input device (108, 109) so as to hold the instrument (231, 241) in place,

    align an orientation of the input device (108, 109) relative to an orientation of the camera tip (311), and

    engage control of the camera tip (311) with the input device (108, 109) prior to controlling the positioning and orienting of the camera tip (311).
13. The medical robotic system (100) according to claim 12, wherein the controller (102) is configured to:

    disengage control of the camera tip (311) with the input device (108, 109) so as to hold the camera tip (311) in place,

    align the orientation of the input device (108, 109) relative to an orientation of a tip of the instrument (231, 241), and

    engage control of the instrument (231, 241) with the input device (108, 109) after controlling the positioning and orienting of the camera tip (311).

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